One of the most costly sub-systems in a wireless communication device is the RF processing chain. The most costly component in the RF processing chain is the power amplifier. To reduce the cost of a transmitter, equipment manufacturers focus on using low-cost power amplifiers. However, low-cost power amplifiers are inherently non-linear. The waveforms of conventional wireless communication protocols that are to be processed by the power amplifier ideally require a linear transfer function to both minimize spectral emissions, via spectral re-growth mechanisms to a neighbor spectrum, and to also control the amount of in-band distortion that is generated by a non-linear transfer function.
Because the distortion mechanism at work in these systems, solutions based on the offline characterization of an amplifier and the employment of a look-up table are inadequate for the combination of bandwidths, modulation schemes and amplifier topologies that are used in current generation communications networks. However, improving linearity can be costly to implement. The algorithms employed in an adaptive processor are complicated and require significant computing requirements. Further, digital pre-distortion processing is often considered a technology that differentiates one equipment provider's base station from another. The ability to customize one's approach to digital pre-distortion is considered valuable. Accordingly, methods for improving linearity in a transmitter of a wireless communication network are desirable.